1. Field of the Invention
The present invention relates to a thermal printer using an interchangeable ink ribbon and an ink ribbon cassette that is detachably attached thereto.
2. Description of the Related Art
In recent years, thermal printers have been mainly adopting a disposable, replaceable ink ribbon cassette for the sake of user's convenience. When the ink ribbon cassette of the disposable, replaceable type is adopted, the ink ribbon stored therein is replaced with a new one after it is used up.
When the new ink ribbon is fixed into the ink ribbon cassette, a user's hand may touch a surface of the bare new ink ribbon. In such a case, ink applied on the surface of the ink ribbon may contaminate the hand. Further, when the hand touches the surface of the ink ribbon, foreign matters such as sweat (finger print) of the hand or dust may adhere to the surface of the ink ribbon. If the ink ribbon to which the foreign matters adhere is used in printing with thermal transfer, printing problems may occur when the thermal transfer is performed, deteriorating image qualities such as color falling-out and color unevenness. Therefore, an ink ribbon cassette for solving such problems is proposed.
The ink ribbon cassette discussed in Japanese Patent Application Laid-Open No. 11-34451 is provided with a lead tape on which the ink is not applied at both ends of the ink ribbon. The lead tape has a length for covering a most outer peripheral surface of the ink ribbon when the ink ribbon is completely taken up by one of a feed real (bobbin) or a take-up reel (bobbin). Thus, the surface of the ink ribbon can be protected by the lead tape and, further, a user can replace the ink ribbon without touching the ink ribbon.
However, in a case of the ink ribbon cassette discussed in Japanese Patent Application Laid-Open No. 11-34451, the ink ribbon is replaced after the ink ribbon is entirely reeled from the feed reel to the take-up reel. Thus, for example, when a size of paper is to be changed, the ink ribbon may be replaced before the ink ribbon is entirely taken up. In such a case, an ink face of the ink ribbon described in Japanese Patent Application Laid-Open No. 11-34451 is exposed and the hand may touch the ink, which may adhere to the hand. Further, in this case, when the ink ribbon is re-used, the image quality may be deteriorated as described above.